Structure and optical properties of the hydrogen diluted a-Si:H thin films prepared by PECVD with different deposition temperatures

The paper deals with the hydrogenated amorphous silicon (a-Si:H) films about 300 nm in thickness prepared by using rf-PECVD with hydrogen dilution R = 10 of the silane source gas in the amorphous growth regime onto clean Corning Eagle 2000 glass substrates at different deposition temperatures ranging from 50 to 200°C. Structural and optical properties of the films were obtained from X-ray diffraction and UV-Vis spectrophotometry. The full width at half maximum of the first scattering peak decreases with increasing of the deposition temperature up to 150°C and then remains constant. Optical band-gaps are from 1.65 to 1.76 eV, which slightly decrease with increasing deposition temperature, whereas the refractive index increases with increasing deposition temperature. This indicates that the density of the films at higher temperature has increased.